Exploring Touchscreen Interface Design for Home Health Management Products: Effects of Button Size and Position on Elderly Users.

The advancement of technology has driven significant changes in user interface design, shifting from traditional button-based interfaces to touch-based graphical user interfaces. As medical knowledge progresses, there is a growing awareness of the importance of self-health monitoring at home. However, due to age-related physiological and cognitive changes, elderly individuals often encounter challenges when operating touchscreen interfaces. This study explores the effects of button size, display position, and color contrast on the usability of touchscreen interfaces for elderly users. A total of 220 subjects, including 110 young people aged 18-35 years and 110 elderly people aged 65 years and above, were recruited for this study. Each subject was required to perform 16 experiments (4 button sizes × 4 display positions). Results indicated that age significantly affected both operation time and error rates, with younger participants exhibiting faster response times and lower error rates. For young adults, button size influenced operation time but not display position or color contrast. In contrast, elderly users performed best with a 16 mm button size and when buttons were positioned at the upper or right side of the display. These findings highlight the importance of designing touchscreen interfaces tailored to the physiological and cognitive limitations of elderly users. Future research should explore adaptive interface designs that dynamically adjust button sizes and layouts to optimize usability across different subjects.